Overview and Issues of the High Plains Aquifer, Oklahoma, 2010 Mark F. Becker U.S. Geological Survey Oklahoma City, Oklahoma

Outline of Presentation Issues (addressed throughout presentation) Location and Setting Oklahoma Water Law Hydrology and Water-Quality Water-Uses and Effects of Withdrawal Future of Irrigated Agriculture Conclusions

Issues 1. Long way from State Capitol 2. Sparsely Populated (Small Legislative Representation) 3. Oklahoma Water Law 4. Groundwater Level Declines 5. Future for Irrigation

Issue #1: The Central High Plains and Oklahoma

Kansas Oklahoma Texas New Mexico Colorado Issue # 2: Sparse Population Estimated Population of Panhandle in 2009 was 30,035

Setting Overlies approximately 7,100 mi 2 in Oklahoma Texas County is Largest Ag Producer in OK Mean annual precipitation around 19-in/yr Temperature range: -25 o F to +110 o F Average lake evaporation = 62-in/year Average runoff (pre-1970) = 0.2-in/year

Land Use (Oklahoma Portion) 56% rangeland 40% dry cropland 4% irrigated cropland

Harvested Acres (Oklahoma Portion) Wheat2,600,000 acres Corn 800,000 Sorghum 700,000 Hay 300,000 Other 65,000

Livestock (Oklahoma High Plains) 620,000 cattle in ,000 cattle in ,000 swine in 1992 > 2,700,000 in 1999

Issue #3: Oklahoma Water Law Oklahoma has a “mining” based regulatory approach to groundwater Property Right Allows for depletion over time Allocations are for high capacity wells and until determined set at 2 acre-ft/ac/yr for land owned Does not recognize hydraulic connection to surface water No effective monitoring Kansas has highly regulated sustainable based law Texas has essentially no jurisdiction over groundwater

Hydrogeology Series of coalescing alluvial fans consisting of sand, clay, and gravel that can exceed 500’ in thickness Well yields can exceed 2,000 GPM Direction of groundwater flow is from west to east Recharge is distributed Recharge is relatively rapid Water-level declines from irrigation withdrawals

Center-pivot Irrigation began in the early 1960’s in Oklahoma

Center Pivot Technology Changed Irrigation Practices Land with rolling topography could be irrigated Circles are 0.5 mile in diameter Each well pumps about 1,500 gpm

Percent Ground-Water Use in the Central High Plains in 1992 Percent Water Use

Water Use in Mgal/d

Groundwater Flow

Saturated Thickness (1998) > <

Issue #4: Water-Level Declines Long-term effects on streamflow Ecosystems Treated municipal wastewater Increased pumping costs Potentially reduces irrigated agricultural opportunities Creates acrimony (whiskey’s for drinking, water’s for fighting)

Water-Level Changes to 1980 Declines more than 100 feet in Kansas, Oklahoma, and Texas Declines of feet widespread Rises more than 25 feet in Nebraska Large areas of little on no change

Water-Level Changes to 1997 Areas of declines have expanded Areas of rises have expanded, especially in Texas and Oklahoma Large rises in Nebraska continue

Water-Level Change from Predevelopment to ± 10 Rise >

Near Guymon Stream Gaging Station Ground Water Well Optima Lake Canton Lake At Beaver At Woodward Near Seiling Well A Lesson in Planning: The Beaver/North Canadian River Basin

Upstream face of Optima Dam in 1990 Aerial Photo by Dale Boyle, U.S. Geological Survey

Increases in Numbers of Large-Capacity Irrigation Wells in the Oklahoma Panhandle

Depth to Water in a key Oklahoma Well in the High Plains Aquifer

Percentage of no-flow days for the Beaver River near Guymon, Okla.

Annual Precipitation (bars) and 10-year moving average (line) for western Oklahoma

Annual flow volume (bars) and 10-year moving average (line) near Guymon ( )

Annual Peak Discharge (bars) and 10-year moving average (line) near Guymon, OK ( )

Recharge Myth #1: Recharge comes from snowmelt in the Rockies Myth#2: Aquifer receives little or no recharge Reality: Distributed recharge from precipitation

Estimated Depth to Water in Feet Tritium Units

 18 O/ 16 O VSMOW ‰ Deuterium VSMOW ‰

Predevelopment Recharge 4.0% of precipitation in sand-dune areas. Averaged 0.69 inches per year. 139,000 acre-feet per year. 14% of model area. 0.37% of precipitation in other areas. Averaged 0.07 inches per year. 85,000 acre-feet per year. 86% of model area.

Cultivated Dryland Recharge Extra recharge due to dryland cultivation 3.9% of precipitation over area in dryland; about 0.65 inches per year 345,000 acre-feet per year

Dryland Recharge Depth to Water

Summary Statistics for Common Ions and Field Parameters

Issue # 5: Future of Irrigation Tied to prices of fuel and crops New technologies allow exploitation of lower well yields Genetically modified crops Low/No Till methods Economy of scale; larger farms, less farmers

Conclusion Politically, not well represented but recognized by the economic value. Contrasting water management strategies on borders Declines in water levels Increased costs Loss of surface water Potential for technological advances to keep irrigated agriculture a component

The End

OWRB Sites

Conclusions NO 3 is elevated in most wells NO 3 is found at all well depths 15 N indicates the presence of animal wastes Changes ahead as more data is evaluated

NO 2 + NO 3 mg/L as N Estimated Depth to Water in Feet OWRB Data

 15 N Air ‰ NO 2 + NO 3 mg/L as N Fertilizer Mixed Animal, Fertilizer, or Soil Animal

Types of Water-Quality Data (OWRB) Field measurements (temperature, pH, alkalinity, O 2, specific conductance) Chemical analyses (common ions, metals, nutrients, 15 N, 18 O, and deuterium) Age dating (tritium, tritium/helium, and 14 C)

Location of Central High Plains NAWQA Study Area New Mexico Colorado Kansas Oklahoma Texas Sub Unit Survey Reconnaissance Public Supply

NO 2 + NO 3 mg/L as N Tritium

Water-quality Data Collected in 1999 Oklahoma water resources board (OWRB)- 12 Wells NAWQA Sub Unit Surveys- 94 wells NAWQA Regional Transect - 5 well clusters (15 Wells) NAWQA reconnaissance - 5 wells NAWQA Public Supply Survey- 15 wells

Outline of Presentation Describe Oklahoma setting and similarities to the entire Central High Plains Describe Oklahoma High Plains study and High Plains NAWQA Water-quality in Oklahoma High Plains Conclusions

 15 N Air ‰ Estimated Depth to Water in Feet Fertilizer Mixed Animal, Fertilizer, or Soil Animal